Changes in Size and Demographic Composition of Transgender and Gender Non-Binary Population Receiving Care at Integrated Health Systems

To examine temporal changes in the number and demographic composition of transgender/gender non-binary (TGNB) population using data from integrated health care systems. Electronic health records from Kaiser Permanente health plans in Georgia and Northern and Southern California were used to identify TGNB individuals, who sought care from January 2006 to December 2014, and the data were analyzed by year, site, age, and sex assigned at birth. In 2006, the number of TGNB people (and corresponding 95% CI) per 100 000 population were 3.5 (1.9, 6.3) in Georgia, 5.5 (4.8, 6.4) in Southern California, and 17 (16, 19) in Northern California. In 2014, these frequencies increased to 38 (32, 45), 44 (42, 46), and 75 (72, 78) per 100 000 population, respectively. When analyzed by age, the most rapid increase was observed among persons 18 to 25 years old, and this increase accelerated after 2010. The ratio of transmasculine to transfeminine persons also changed from 1:1.7 in 2006 to 1:1 in 2014 overall and from 1:1 in 2006 to 1.8:1 in 2014 among persons